Cape Cod Chronicle, November 26, 1998
Text and Photo by William F. Galvin
HARWICH --- Combating shellfish disease and restoring shellfish habitat were only a couple of the topics digested by Natural Resources Officer Thomas Leach this week during a four day trip to Hilton Head to attend the International Conference on Shellfish Habitat Restoration. Leach was selected to represent Barnstable County shellfish wardens at the conference and his trip was paid for by the Southeastern Massachusetts Aquaculture Center, located at Massachusetts Maritime Academy.
The focus this year was on restoration of oyster habitat, explained Leach, but the conference provided an opportunity to examine the latest scientific study being conducted on shellfisheries and to see how people from around the world are managing their resources. There is growing commitment to the restoration of degraded coastal ecosystems throughout the world and Leach said it was great to hear what steps are being taken in Japan, Denmark, France and Canada as well as within the many estuaries along the coastal United States. "I came away from there thinking Barnstable County has a long way to go," explained Leach of steps being taken in other areas to clean up shellfish grounds. "Shared knowledge is so important, we're not on the cutting edge here."
The natural resources officer left that conference with the understanding fecal coliform pollution is one of the major threats to shellfish grounds and that other jurisdictions are more proactive in instituting corrective measures. "There is a lot of targeting of septic systems," stated Leach. "Our approach is to take care of it (failed systems) when a property sells. Other states are way ahead of us. They target a situation and get it addressed." He cited the efforts underway in Chesapeake Bay to restore the oyster industry, which has fallen on hard times in major part due to poor water quality conditions. He cited studies taking place within the scientific community designed to take guessing out of identifying the sources of pollution. They are using DNA testing to determine whether accelerated fecal coliform counts are being generated by humans, waterfowl or other animals in the area. "They can tell if the pollution is coming from nature or the housing development along the shoreline," stated Leach. The natural resources officer said he learned more about building three-dimensional reefs to improve oyster habitat. The practice has been to scatter spent shells on the bottom of Herring River to provide a substrate for oyster spat to attach. The better approach is to dump these shells in piles that rise from the bottom of the river. The reason, explained Leach, is the dissolved oxygen levels at the bottom of the river are virtually non-existent, making it difficult for the oyster seed to survive. The higher up in the water column, the better the conditions are for survival, stressed the natural resource officer. There was great emphasis, during these seminars, on the importance of dissolved oxygen levels to a successful shellfish habitat, he said.
"Measuring dissolved oxygen levels is one of the most important parameters because you are measuring the health of an estuary," stated Leach, who also pointed out his department purchased a YSI Meter last summer in order to get accurate measurements for use in conjunction with the town's shellfish laboratory. Another area Leach found particularly interesting focused on shellfish disease and how it is transported from one embayment and estuary to the next and transmitted to shellfish there. He cited a parasitic disease known as QPX, which attacks hard shell clams, as a particular interest because it has devastated crops in Provincetown and Duxbury and could at some point reach the southside of Cape Cod. The good news is, explained Leach, a study conducted by Rutgers University has shown that parasite has as yet had no impact on hatchery stock, which the town grows out in its shellfish laboratory in Wychmere Harbor and then plants in the wild for recreational and commercial harvest. The hatchery stock a year and a half after being planted in the wild has shown no signs of this parasite, explained Leach.
The Harwich natural resources officer said Cape Cod was well represented at this conference. He joined Richard Kraus of ARC, Inc. in Dennis, a private shellfish hatchery and research center, who was also sponsored by SMAC and representing private industry. Leach said he has also volunteered to serve on an international committee working on developing uniform shellfish density for hard shell clams. The group will function by communicating through e-mail, he explained. "For me it was definitely worth the trip, it helped me renew my energy in that area," stated Leach.